高温胁迫下小麦生理指标的主成分分析及综合评价

Principal component analysis and comprehensive evaluation of the physiological indices in wheat under high temperature resistance

为了解小麦对花后高温胁迫的生理响应,以洛旱2号、郑麦366等26个品种为材料,测定高温胁迫(搭棚增温)下和大田自然生长条件(CK)下叶片的相对含水量、可溶性蛋白含量、丙二醛(MDA)含量等11个生理指标及籽粒产量。结果表明:高温胁迫下,26个小麦品种的光合速率、蒸腾速率、气孔导度、SPAD值、叶片相对含水量整体呈下降趋势,可溶性蛋白含量、丙二醛(MDA)含量整体呈上升趋势,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的变化趋势并不明确;以11项指标的抗逆系数作为衡量抗高温性的指标,主成分分析结果表明,11个生理指标可以综合成5个相互独立的综合指标,其累计贡献率为80.561%;根据产量相关指标可将26个小麦品种划分为4类,周麦22、新麦11号等11个品种为中抗高温型品种,郑麦366、兰考矮早8等10个属于高抗温型小麦品种,西农979、洛旱6号等4个品种属于低抗高温型品种,洛旱2号的千粒质量热感指数和产量的热感指数均大于2,且千粒质量的抗逆指数和抗逆系数均小于80%,属于高温敏感型品种。结合D值聚类分类结果综合判断,郑麦366、兰考矮早8、冀麦47属于高抗高温型小麦品种;新麦11、周麦19、郑麦7698、丰德存麦1号属于中抗高温型小麦品种;西农979、洛旱6号、北京8号属于低抗高温型小麦品种。

In order to understand the physiological response of wheat to post-anthesis high temperature, 26 wheat cultivars including Luohan2, Zhengmai366, etc were screened. And 11 physiological indexes including the content of leaf relative water content, soluble protein, malondialdehyde(MDA), etc were analyzed under post-anthesis high temperature stress(plastic-covered tunnel) and natural growth conditions(CK). The results showed that under high temperature stress,the change trend of the photosynthetic rate, transpiration rate, stomatal conductance, chlorophyll content, and leaf relative water content decreased as a whole, while the change trend of soluble protein content and malondialdehyde(MDA)content increased as a whole, but the change trend of superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT)were not obvious in 26 wheat cultivars. And we took each high temperature resistance coefficient as the index of high temperature resistance, and evaluated different cultivars wheat comprehensively through principal components analysis.The results showed that 11 indices were transformed to 5 independent comprehensive indices, which total cumulative rate reached to 80.561% through analysis of principal component. Based on the relevant indexes of yield, 26 wheat cultivars were divided into 4 groups. The first category included 11 cultivars, such as Zhoumai22, Xinmai11 belonged to the medium-level high temperature resistant wheat cultivars. The second category included 10 cultivars, such as Zhengmai366, Lankaoaizao8 belonged to high-level high temperature resistant wheat cultivars. The last category included 4 cultivars, such as Xinong979, Luohan6, belonged to low-level high temperature resistant wheat cultivars.Among them, Luohan2 was high temperature sensitive cultivar and it’s heat sensitivity index of 1000-grain weight and yield were higher than 2, the index and coefficient of resistance of 1000-grain weight were less than 80%. Comprehensive judgment based on D-value clustering classification results, Zhengmai366, Lankaoaizao8 and Jimai47 belonged to the high temperature resistant wheat varieties;Xinmai11, Zhoumai19, Zhengmai7698 and Fengdecunmai1 belonged to the medium-high temperature resistant wheat varieties;Xinong979, Luohan2 and Beijing8 belonged to low and high temperature resistant wheat cultivars.